Radiators are commonly used in automobiles having an internal combustion engine to convey heat away from hot engine components to the cooler ambient air. A radiator is part of a closed loop system wherein the radiator is hydraulically connected to passageways within an engine through which a heat transfer fluid, such as a mixture of water and ethylene glycol, is circulated.
A typical radiator is formed of a central core having a multitude of parallel tubes with fins therebetween to increase the surface area for optimal heat dissipation. Hydraulically attached to either end of the core that corresponds with the tube openings is an end tank. After absorbing heat from a heat source, the heat transfer fluid enters a first end tank where the fluid flow is uniformly distributed through the parallel tubes. As the fluid flows through the parallel tubes to the second end tank, heat is radiated to the ambient air. To assist in the heat transfer, a stream of ambient air is blown perpendicularly relative to the radiator core through the fins. The cooled heat transfer fluid then exits the second end tank returning to the heat source to repeat the heat transfer process.
Some motor vehicles have multiple radiators to cool a plurality of heat sources such as an internal combustion engine, transmission, electronic components, and charge air coolers. Typically, to meet the packaging requirements of a vehicle's engine compartment, the multiple radiators are stacked. A major draw back of stacking radiators is a decrease of heat transfer efficiency due to the increased pressure drop through the stack of radiators. There are other drawbacks of utilizing multiple radiators such as increase in vehicle weight, systems complexity, and manufacturing cost.
To address the shortcomings of using multiple radiators, it is known in the art to combine individual radiators utilizing a common core. Shown in FIG. 1 is a prior art combination radiator 1. The combination radiator includes a single core 10 assembled from multiple of parallel tubes 20. Longitudinally attached to either end of core 10 corresponding to the tube openings 35a, 35b, is an end tank 30a, 30b, respectively. Each end tank 30a, 30b has a transverse partition 40a, 40b, respectively partitioning the end tanks into compartments 50a, 50b, 60a, and 60b. Each of the end tanks is typically of metal construction with stamped openings 70 on a side wall 15 to accommodate the tubes openings 35. The tubes 20 are typically affixed to the side wall 15 of the end tanks by brazing or welding thereby effectively segregating the core 10 into a first core portion 80 and a second core portion 85.
For a combination radiator used to dissipate heat from two different heat sources in a vehicle, the first heat transfer fluid from the first heat source (not shown) enters the first inlet 90a to compartment 50a, travels through tubes 20 to compartment 50b, and then exits first outlet 90b returning to the first heat source. The second heat transfer fluid from the second heat source (not shown) enters the second inlet 95a to compartment 60a, travels through tubes 20 to compartment 60b, and exits second outlet 95b returning to the second heat source. The two heat transfer fluids are cooled by the same airflow which sweeps through core 10.
Utilizing a combination radiator to dissipate heat from multiple heat transfer fluids having different thermal and pressure cycle requirements may result in failure of structural integrity in transverse partitions 40a, 40b. The expansion differential between compartments 50a, 60a of an end tank 30a caused by the difference in temperature and pressure of the respective heat transfer fluids increases the stress on transverse partition 40a. Due to excessive stress, transverse partition 40a may fail thereby allowing the heat transfer fluids to intermingle resulting in potential damage to the heat sources being cooled. Furthermore, transverse partitions 40a, 40b does not offer a significant thermal barrier between the two different heat transfer fluids thereby resulting in decrease efficiency of heat dissipation of the cooler heat source.
For a combination radiator dissipating heat from heat transfer fluids with significantly different thermal and pressure cycle requirements, there is a need for a combination radiator with an end tank assembly with a robust separator that offers superior structural integrity and thermal isolation. There also exists a need that the end tank assembly can be manufactured easily and economically.